


For Science

by eisneRiegan



Series: Housemate AUs [1]
Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe, Alternate Universe - Modern Setting, Alternate Universe - Roommates/Housemates, Gen, Science Bros, Science Experiments
Language: English
Status: Completed
Published: 2019-12-06
Updated: 2019-12-06
Packaged: 2021-02-26 07:34:23
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,417
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21689938
Author URL: https://archiveofourown.org/users/eisneRiegan/pseuds/eisneRiegan
Summary: Claude and Sylvain are housemates.Claude got bored and roped Sylvain into some science experiment.
Series: Housemate AUs [1]
Series URL: https://archiveofourown.org/series/1570345
Kudos: 23





	For Science

**Author's Note:**

> Took a break from writing Claudeth to make a light (chaotic neutral-ish) story.
> 
> Inspired by NileRed's experiments over at YT.

"Hey, want to ruin a few microwaves and annoy Byleth?"

"Excuse me, what?"

Sylvain stared at Claude for a heartbeat, then grinned.

"Sure, I'm game with that."

Claude returned his grin. "Knew you'd agree. Come on, I have things already set up in the third floor."

The two of them rented one side of a duplex, which has three floors, three bedrooms and two baths since it's close to their workplace and because their working hours are erratic. They couldn't be bothered to commute for two to three hours in the morning and another two or three hours going home.

Sylvain is working as a clinical biochemist for a nearby hospital and Claude works an Analytical Research assistant for a pharmaceutical company. There are times they have to come in early or go home late and they don't really have the energy to go through a hellish commute.

The two of them are chemistry graduates (though on different specialties), with Sylvain being Claude's upper-class man and they met through a common friend when Claude started working. They didn't like each other at first but after a few rounds of drink and getting to know each other, no one could separate the newly formed chaotic best friends.

One would think that just because they graduated from the same college is the reason why they're friends.

But it's not.

The reason why they're friends is because both of them thinks that the chemistry industry sucks big time.

They used to have dreams about working in a lab with other chemists and making many researchs that can pave the way for new discoveries.

Reality, however, is quite disappointing.

Sylvain had struggled a lot on getting a job, refusing on taking up a job in his family's business which is out of his expertise. When he graduated, he worked part-time on many small laboratories but get laid off eventually due to being contractual. He then pursued a medicinal certification and it took him a while but now he's secured on his job and earning quite well for a single man with no obligations to any wife or child.

Claude was lucky enough that the place he applied for on-the-job training took him in right after he graduated, as the team liked him. At first he was flattered but three months into working with them professionally, he noticed that the senior chemists are just dumping the work on him. The countless hours he put in for that research and they all claimed credit for it when it's all Claude who did the work. He quit the job and Sylvain helped him get into the pharmaceutical company using his connections.

Claude's family actually own a company that can hire the two of them as chemists but Claude doesn't really feel like going there yet.

Doing perfume and cosmetic chemistry isn't to his liking. He knows Sylvain would take up the job if he offered, knowing how much he likes impressing women, but he seems to be enjoying helping people out in the hospital.

Besides, Sylvain can't attain the senior position right away for he lacks the experience. Claude has minimal experience on it, growing up with parents who made it as their living.

Maybe he could ease Sylvain into it and then drag him to their family's business. He'd like to have a friendly face in a really competitive workplace like that.

But he'd do that on another time.

Right now, they're going to do some science for fun.

To de-stress from everything.

And annoy the owner of the duplex, Byleth Eisner, who lives next door with her father, six cats and two dogs. They don't really know what kind of work she does, since she seem to be always around when they're doing something idiotic. Her father is rarely home due to his work as a consultant that made him travel around a lot.

Like that one time when they oxidised glycerin with potassium permanganate because they were bored. The fire wasn't that big in the bowl where they had placed it. It was also in the safety of a fume hood they had requested to be installed when they moved into the duplex just in case. But she came in to invite them over for lunch and then saw the two of them sitting there casually, watching the fire that is dancing around the bowl.

She was horrified at first because no one can predict when the fire will go wrong, but then stuck around when they explained the basics for it and watched another oxidisation curiously.

Or that other time when she chanced upon Sylvain blowing into a straw and making bubbles in the lab flask with a clear liquid in it. Claude made Byleth wait for the liquid to turn into a milky one, noting it down on a notebook for how long it took Sylvain to finish before he entertained her questions.

Or when she almost kicked them out thinking they were making meth crystals but turns out it was just sugar crystal candy. Claude even handed over to her a "fast rock candy crystal" stick that he proudly told her was their experiment on how fast they can make such thing because no one has time to wait for a week or two for the crystals to form.

Or that really dangerous time when they had Hubert, another fellow graduate from the same college, over as he wanted to use their little laboratory to make a liquid carcinogen away from the ever watchful eyes of Edelgard who happens to be his employer. Sylvain and Claude were nervous when he was making it, knowing that Byleth would surely kick them out once Hubert makes a mistake with that thing.

They prefer harmless and fun chemistry experiments in that place.

What Hubert made in their little space was equivalent to a deathly liquid. Claude made Hubert promise, as he finishes up his work, that he will not do any more dangerous stuff like that in their presence and their laboratory.

Byleth will kill them if she finds out what the hell is that thing.

When Hubert left with that really omnious looking liquid that he poured into a round flask, with a stopper that has been soaked in sulfuric acid, a plastic pin snapped into place to prevent any kind of leakage and placed it inside a well-cushioned thick case, the two of them properly disposed of all the materials he used and making sure that everything is sterilised thrice for good measure.

There are other circumstances that they almost got kicked out of the duplex apart from their experiments, but thankfully Byleth and her dad are nice to them and so they tried to keep their dumb things to a minimum.

But not today.

Today is a good day for dumb things.

They entered the room at the third floor and Sylvain immediately saw at least three microwaves at one side of the room.

"Claude, how much money did you burn to get these microwaves?" Sylvain asked him.

"It was on sale." Claude replied defensively. "Unless you want me to use the microwave Byleth provided us?"

"I think she's at the end of her patience with us if we ever destroy something in here." Sylvain informed him. "I won't risk getting kicked out of this place since it's such an ideal location..."

"Well, don't complain about the money I used on getting these."

"What do you have in mind for these microwaves?"

Claude grinned. "We're going to watch some pretty plasmas."

Sylvain raised an eyebrow at that. "What, you also bought grapes?"

"Grapes and many others. Let's see how many times we can put up a pretty display."

"You don't plan on recording them, do you?"

"Well...I didn't at first. But now that you mentioned it, maybe I will. Help me drill out a hole at the back of these microwaves."

"Why at the back?"

"Well, we don't want anything blocking our view from the front, right?" 

"You are not going to use my phone to record this."

"You are no fun."

Sylvain grabbed a power drill from one of the kits in the other side of the room and Claude turned the microwaves around. The ginger looked around for a nearby power supply and plugged it in while his friend rummaged around for an action camera (that may have belonged to Byleth as she likes hiking on some weekends and recording her trip) that is laying about and some aluminum tape.

"Where should I drill?" Sylvain asked as he gave up on the power socket and opted for an extension cord.

Claude returned to the table with the small camera and the tape. He opened the first microwave and tiptoed to look at the other side for an estimate.

"Maybe here. It's high enough to see everything and not ruin the overall electrical wirings." Claude replied, pointing at the spot.

Sylvain placed the tip of the drill and Claude immediately withdrew his finger.

"Hey, don't cut my finger with that."

"Don't be paranoid. I haven't even turned it on yet." Sylvain assured him then he turned it on, drilling a small hole.

"This good enough?" he asked. Claude stood next to him and placed the camera's lens at the hole. He turned it on and checked the angle at the mini display.

"Mm, perfect."

Sylvain frowned at the camera he's holding. "Isn't that...does Byleth even know you have that?"

"I borrowed it from her some time back for one experiment. But I never got around to do that said experiment so I'm using it here."

Sylvain doubted that answer as Claude taped the camera securely beford turning it around again. He pressed the on button for the camera with the remote control.

"You want to test the grapes?" He asked as he unplugged the drill and replaced it with the microwave's plug.

"Yeah, sure. This is going to be boring though. We have seen it many times."

"In recordings, yeah." Claude agreed as he got two grapes placed it inside the microwave with a small microwavable dish so that it'll stay in place. "But not in actual and in slow motion."

He set the timer on and they watched the grape inside turn.

They look like two idiots waiting for a popcorn to finish in front of the microwave.

The grapes started to spark a little as it continued to rotate, then the blue plasma started to appear in short sparkling bursts then fizzled out as the grapes rolled to their sides and no longer in contact with each other.

They watched it for a few more seconds until the timer on the microwave turned off.

"Yeah, you know what, that was really...underwhelming." Claude admitted as he let the grapes cool off. "You think it's safe to eat after what happened?"

"Try it and let me know what will happen to you." Sylvain told him, to which Claude stuck his tongue out at him childishly. "Let's put in aluminum foil."

"With beaker to cover it up?"

"Nah."

Claude chuckled as he carefully took out the dish with the grapes on it and disposed of it properly. Sylvain crunched up a few pieces of aluminum foil and placed them in the middle of the rotating tray.

"Ready?"

"Do the honor, Mr. Gautier."

Sylvain rolled his eyes at that and then pressed the button.

The foil inside the microwave didn't do anything for the first few seconds and then it ignited, giving off a pretty bright blue plasma that dances around it. But it shifts to a noteable yellow every now and then.

"Sick." Claude laughed.

"Agreed. That is the prettiest light I've seen."

"Don't go hittin' on it, Sylvain. It can burn you so badly like that one time when Ingrid insulted you. I could buy a plasma ball if you'd like. Much safer."

Sylvain pushed Claude away, annoyed. "Oh shut up."

The microwave turned off and they stood there, wondering what else they could do with the microwaves.

"Let's try with a match." Claude suggested.

"Open fire in a microwave doesn't sound safe."

"Well, we have a lot of beakers to contain it."

Sylvain scrunched up his nose.

Well, they do need a new set of those things. They had already burned out their stocks of test tubes literally, when they made test tube liquid rockets with hypergolic mixtures. Their flasks have all of Claude's failed ferrofluid that he can't make pointy spikes at all when he uses a magnet.

("I want to make a literal dark spikes, Sylvain. Imagine Hubert being amused by it!" Claude reasoned out. "Don't you want to see him chortle darkly as he move the magnet around and making those spikes inside a glass?" "No, I don't want to see him like that, Claude. It's giving me the chills.")

And it's a good excuse to buy new ones if their beakers are ruined thanks to this microwave experiment.

"Fine. But you're splitting the bill with me once we order new sets." Sylvain told him, putting his hands on his waist.

"Fine by me. I've been wanting to buy a different brand after all." Claude answered as he reached for the closest beaker.

Sylvain placed a match in the middle of the microwave, lighting it with the ignition stick lighter they always use for barbecue days. Claude then covered it with a beaker and closed the microwave door.

"For some reason, I am excited for this." Claude said to Sylvain who then pressed the start button on the microwave.

The plasma from the fire appeared almost immediately. It looks like a cgi effect, dancing around the beaker. The yellow light from it completely disappeared after a few seconds and was replaced by a blueish light.

"I like my plasma blue." Sylvain said to no one in particular as it died out.

Claude was tapping his chin, thinking of something as he stared at the microwave. He then opened it, tentatively reached for the beaker (without anything to protect his hand from the imminent danger of touching hot glass) and slightly burned his fingertips.

"Genius move." Sylvain chortled. Claude ignored him and reached for the lower part of the beaker, which is just warm.

It was kind of stinky, probably thanks to the potassium and sulfur in the matchstick. The two of them checked the beaker, which has a very obvious discoloration from where the plasma had danced around.

"Is there a way we can record it without it rotating? It's not much to look at when it's moving around." Claude asked as he set aside the beaker for disposal later and throwing the used matchstick into a nearby bin.

"Turn the tray over." Sylvain suggested. "That way, it won't rotate since it's not touching the rotating thing underneath."

Claude did as he suggested and placed a match inside (with a stabilizer tray for it to sit on), setting it alight with the lighter then covered it with a fresh new beaker. He then started the microwave again and waited for the plasma to appear.

It didn't appear.

The fire went out inside the beaker.

"I don't understand." Sylvain muttered as the timer went down to zero and the microwave turned off.

"I don't understand it either." Claude said, frowning as he placed his hands on his hips and tapped the floor with one foot patiently. "There's no way we got lucky with the first tries..."

"Or maybe we did get lucky? But that doesn't make any sense. Why would this one fail?"

"You think it's because the fire went out fast?"

"So we light more matches?"

"Wouldn't hurt to try." Claude told him, getting several matches and placing it inside the microwave. He lit them up one by one and then covered with a new beaker.

They are going through their beakers fast and they're only in this experiment for roughly less than thirty minutes. They still have two microwaves to ruin.

Sylvain started the microwave again but still, the plasma didn't appear. Claude made a really disgruntled noise as the microwave turned off without anything happening.

"Let's try with aluminum. And without the beaker." Claude told Sylvain who carefully took the beaker out and the spent matches. The ginger then placed a foil inside, closed the door to the microwave and turned it on.

Nothing happened.

The foil sat there, looking like it's staring at them and mocking them for their failed experiment.

"Let me try something." Sylvain said suddenly as he opened the microwave again and took out the contents. He then turned the tray back to its original side and he placed a new foil and beaker inside.

When he turned it on, the plasma appeared once again, bathing the inside of the microwave with its blueish light and ruining the beaker.

"I guess the rotation is a requirement."

Claude scowled at that. "We can't get a nice recording of it if it always go around the..." He trailed off, making Sylvain look at him warily.

"I've got it." Claude grinned suddenly as he carefully took out everything from the microwave. "We have to drill another hole."

"What? Why?"

"Because I am placing our things directly on the rotating thing. And without the tray to elevate it, we can't get a clear shot."

Sylvain sighed as he took up the drill again. The new set up didn't take them long and Claude plastered a big aluminum tape over the old hole they had drilled.

"Perfect." Claude said as he placed an unlit match and checked the display at the back of the camera. They got the height correctly.

"Time to light it." He cheerfully told Sylvain. Sylvain lit the match up and covered it with a beaker. Claude then turned it on and finally, they got their plasma in place.

"Sweet."

Sylvain noticed the plasma suddenly sliding down directly at the rotating thing the match is resting on. But it didn't give off any fire.

Yet.

Then it did.

"Oh crap." Sylvain cursed as he turned it off before it could make a bigger fire.

"Aw, we were having a good time." Claude pouted. Sylvain shot him an annoyed look.

"We are not going to set the room on fire."

"Fine. We'll use aluminum then. Much safer, right?"

Turns out, it wasn't safe at all.

The microwave still set itself on fire whenever they turn it on and Sylvain only looked at Claude with that annoyed older brother vibe.

"This one's broken now." He told Claude. "I am not going to entertain any objection from you and let's just move on to the next microwave."

Claude agreed to do it and they set up the next microwave for their experiment. He also placed a small glass dish on top of the rotating thing to act like a tray for their test objects.

He placed aluminum on top of it and covered it with a beaker.

Finally they got a nice, clean shot of the cgi-like plasma that somehow stayed at the top of the beaker like some luminescent cloud then gradually slid down as the rotation slowed, slipped over the small tray and touched the rotating thing underneath before it turned off.

The two of them looked at one another, unsure if it's safe to use again.

The only way to know is to do it again.

"We are running out of beakers." Claude told Sylvain as he handed it over. "We only have two left."

Sylvain placed a thicker and bigger foil inside the microwave and covered it.

"That yellow light is really getting to me." Sylvain commented as the plasma turned from yellow to blue. "What's causing it?"

"Maybe our foil got contaminated by something?" Claude prompted, looking at the foil in one corner. "We should have had taken a spectrometer to check..."

"Yeah and...oh shit." Sylvain said out loud as the inside of the microwave have that small fire underneath. They quickly turned it off.

"We might as well use the last beaker." Claude finally said after a moment of silence.

"No, save it. Let's try with forks."

"What? No." Claude defensively said. "I am not going to buy new forks if we ever botch them."

"Hey, weren't you the one who suggested we should ruin a few microwaves?"

"I said microwaves only and a few beakers. Not forks. You have no idea how hard it was to look for such forks that has definite weight in them compared to those tin-like ones you used to have around here."

"I don't need a fancy fork. As long as it can pick up the food and do its thing."

"Let's try with zinc granules for last." Claude diverted the topic, to save his precious forks. Sylvain rolled his eyes at that.

"Fine. I think I have some over at the cabinet."

He went over and rummaged around the said cabinet and found the jar of zinc granules at the very back.

"Huh, it still has a lot of content than I remember."

"Wonder later, and give them to me." Claude said, his hand outstretched. Sylvain handed it to him and he poured out a decent amount onto the little tray before popping it back inside the microwave with the beaker covering it.

He turned it on and it sparked for a moment then the plasma went to the top of the beaker. But at the same time the damaged microwave lit up with fire underneath the small tray, the flames licking the insides of the beaker.

This time though, Sylvain didn't turn it off.

"Seeing that fire makes me want to have some s'mores." Claude admitted, embarrassed.

"I was thinking of kebab." Sylvain told him.

They laughed at one another. Maybe after this experiment, they're getting some food to ease their crazy ideas.

They watched it for a couple more seconds. Then they heard Byleth arriving next door and they immediately turned it off.

The two of them moved around quickly, placing things carefully out of the way for disposal later when Byleth is asleep.

They're like kids trying to clean up their room before their mother finds out they haven't done it while she was away.

Claude almost dropped the used beakers when Byleth rang the doorbell to their side of the duplex.

"Careful with that!" Sylvain hissed at him.

"I am! Why is she home this early?"

"Don't ask me! Clean up here and I'll go downstairs so that she'll not get suspicious."

"What? You're not going to help me with cleanup?"

"Hey, it was your idea in the first place."

Downstairs, Byleth rang the doorbell again and frowned when no one's answering the door.

She knows they're home, having memorized their schedule. She thought she could have some company for dinner later.

When she turned to leave, Sylvain yanked the door open, surprising her.

"Hi! Yeah, sorry if it took me a while." Sylvain panted, thankful he did not trip down the stairs. "I was...in the bathroom. Yeah...the bathroom."

Byleth blinked at him then smiled. "Oh, sorry to have interrupted with that...bad tummy?"

"Huh? Oh, no no... Not at all..." Sylvain laughed nervously. "I just...well, you know. Had a little too much coffee...is there anything you need?"

"Oh, nothing important. Just thought of inviting you two over for dinner. Claude is home, right?"

"Yep, I'm here." Claude called from the second floor landing, poking his head to look at the door. He grinned at her.

"What's up?"

"I'm making dinner later, so come over okay?"

"Oh, cool. Thanks mom."

Byleth frowned at him, while Sylvain raised an eyebrow at him. Claude went down to stand next to his housemate.

"What? She does behave like a mom. Making dinner for us and all that."

"Can't I be a concerned landlady?" Byleth pouted.

"Landlady has that strict ring to it. And you're not really that strict with us." Claude winked at her. "After all of our experiments..."

Byleth shrugged at that. "Well, you're the only tenants my dad likes a lot. So, dinner later?"

"Sure, we'll be there." Claude gave her a cheerful wave. Byleth turned to walk away but then stopped to look over her shoulder.

"Claude, can you return my camera later? I need it for my hike this weekend."

"Sure, I can do that. No problemo."

"And maybe you two want to hike with me? So I can keep a close eye on you, make sure you're not doing anything stupid."

"A hike sounds nice." Sylvain agreed. "Maybe we can tag along."

Claude looked at him questioningly. When they finally closed the door, Sylvain turned to him seriously.

"We have to keep reassuring her that we're not here to blow the house up."

"You sure you're not just hitting on her so that we can have lower rent?"

"Of course not! How dare you accuse me of flirting with our landlady, even if she's actually quite a looker..."

"You see Sylvain. I can never figure out if you're flirting or not. Sometimes I think you're even flirting with me. It's like...you're always flirting with anyone and anything."

"It's called being nice and courteous. Gods, why do people see me only as that kind of guy?" Sylvain shook his head. "Anyways, don't forget to transfer the recordings we had of that microwave plasma experiment. We don't know what her reaction will be once she sees it."

"Leave it to me."

Sylvain should have known better.

Claude did not transfer the video recording to his computer, and instead got so immersed in one research paper he's reading about medicinal drugs that he forgot to do it before returning the camera that evening.

When Byleth saw the recording when he returned the camera that night, and seeing how they didn't even tried to put out the fire in one part of their experiment, the two of them got scolded so badly that they felt like kids again.

It reminded them of that really strict teacher they have back then.

And Claude has the audacity to nickname her "Teach" because of that.

Needless to say, Byleth made it a requirement for them to join her in her hikes twice a month, to make sure they're not getting themselves into trouble they can't get out from.

At least they have an extra microwave, that was saved from their experiment due to Byleth's arrival, to make popcorn with at home. 

**Author's Note:**

> For the love of gods, don't ever do this kind of experiment. Have mercy on your microwaves.
> 
> If you want to see microwave plasma, go watch NileRed's video about it. The ferrofluid and liquid carcinogen vids are there too.
> 
> The bit where Sylvain is blowing bubbles is an experiment with limewater and carbon dioxide.


End file.
